|
|
| Line 1: |
Line 1: |
| [[Image:1bu6.gif|left|200px]] | | {{Seed}} |
| | [[Image:1bu6.png|left|200px]] |
|
| |
|
| <!-- | | <!-- |
| Line 9: |
Line 10: |
| {{STRUCTURE_1bu6| PDB=1bu6 | SCENE= }} | | {{STRUCTURE_1bu6| PDB=1bu6 | SCENE= }} |
|
| |
|
| '''CRYSTAL STRUCTURES OF ESCHERICHIA COLI GLYCEROL KINASE AND THE MUTANT A65T IN AN INACTIVE TETRAMER: CONFORMATIONAL CHANGES AND IMPLICATIONS FOR ALLOSTERIC REGULATION'''
| | ===CRYSTAL STRUCTURES OF ESCHERICHIA COLI GLYCEROL KINASE AND THE MUTANT A65T IN AN INACTIVE TETRAMER: CONFORMATIONAL CHANGES AND IMPLICATIONS FOR ALLOSTERIC REGULATION=== |
|
| |
|
|
| |
|
| ==Overview==
| | <!-- |
| BACKGROUND: Glycerol kinase (GK) from Escherichia coli is a velocity-modulated (V system) enzyme that has three allosteric effectors with independent mechanisms: fructose-1,6-bisphosphate (FBP); the phosphocarrier protein IIAGlc; and adenosine nucleotides. The enzyme exists in solution as functional dimers that associate reversibly to form tetramers. GK is a member of a superfamily of ATPases that share a common ATPase domain and are thought to undergo a large conformational change as an intrinsic step in their catalytic cycle. Members of this family include actin, hexokinase and the heat shock protein hsc70. RESULTS: We report here the crystal structures of GK and a mutant of GK (Ala65-->Thr) in complex with glycerol and ADP. Crystals of both enzymes contain the same 222 symmetric tetramer. The functional dimer is identical to that described previously for the IIAGlc-GK complex structure. The tetramer interface is significantly different, however, with a relative 22.3 degrees rotation and 6.34 A translation of one functional dimer. The overall monomer structure is unchanged except for two regions: the IIAGlc-binding site undergoes a structural rearrangement and residues 230-236 become ordered and bind orthophosphate at the tetramer interface. We also report the structure of a second mutant of GK (IIe474-->Asp) in complex with IIAGlc; this complex crystallized isomorphously to the wild type IIAGlc-GK complex. Site-directed mutants of GK with substitutions at the IIAGlc-binding site show significantly altered kinetic and regulatory properties, suggesting that the conformation of the binding site is linked to the regulation of activity. CONCLUSIONS: We conclude that the new tetramer structure presented here is an inactive form of the physiologically relevant tetramer. The structure and location of the orthophosphate-binding site is consistent with it being part of the FBP-binding site. Mutational analysis and the structure of the IIAGlc-GK(IIe474-->Asp) complex suggest the conformational transition of the IIAGlc-binding site to be an essential aspect of IIAGlc regulation.
| | The line below this paragraph, {{ABSTRACT_PUBMED_9817843}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 9817843 is the PubMed ID number. |
| | --> |
| | {{ABSTRACT_PUBMED_9817843}} |
|
| |
|
| ==About this Structure== | | ==About this Structure== |
| Line 32: |
Line 36: |
| [[Category: Crystal structure]] | | [[Category: Crystal structure]] |
| [[Category: Glycerol kinase]] | | [[Category: Glycerol kinase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:57:35 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 19:43:37 2008'' |
